Inhibition of virulence factors and biofilm formation of Bacillus licheniformis and Bacillus amyloliquefaciens by Nisin

Abstract

Quorum sensing (QS) plays a key role in the spoilage of food spoilage bacteria, and inhibiting the spoilage phenotype by interfering with QS has become a hot research topic in recent years. Previous studies showed that Nisin had a wide range of targets and its bacteriostatic activity focused on inhibiting Gram-positive bacteria. In this paper, we investigated the effect of Nisin at sub-MIC on virulence factors and biofilm formation of the common food spoilage bacteria Bacillus licheniformis DSM13 and Bacillus amyloliquefaciens CC178. The results showed that the amount of biofilm formation, EPS production, protease activity and amylase activity, promoter expression, and motility of the two bacteria showed different degrees of reduction, but hardly affected the normal proliferation of the bacteria; The impaired biofilm integrity and a large amount of matrix reduction were observed by SEM; The molecular docking demonstrated that Nisin non-competitively bind to the com P protein-specific of the two bacteria through hydrogen bonding sites, affecting the binding of com X to com P. These results suggested that low concentrations of Nisin effectively reduced the risk and safety hazards caused by QS of G+ and is a promising QS inhibitor.